Sorry, this is not a bug, it is "progress".
After searching some more I understand there now is a separate mailer.
In that mailer I can now click on
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=138288
and get the message:
Error showing url: There was an error launching the default action
command associated with this location.
Probably this is part of the "progress" too...